1. Field of the Invention
The present invention relates generally to fastener extraction devices and, more particularly, to fastener impact devices for extracting a fastener from or inserting a fastener into a workpiece by striking the device with a hammer to force grasping projections into the head of the fastener, then removably securing a hand tool to the device to impart rotary motion to the device thereby rotating the fastener in a predetermined direction.
2. Background of the Invention
Fastener extraction devices are well known and are generally designed to remove broken stud bolts and to extract one-way fasteners by the device with a rotary drive tool such as a ratchet. However, few of the prior art fastener extraction devices are designed to receive a strike from an impact tool such as a hammer to force “biting” edges or projections of the extraction device into the head of the fastener to allow the extraction device to “grasp” the fastener head and forcibly rotate the head in a predetermined direction with a rotary drive tool. Examples of prior art fastener extraction designs that can receive a forceful blow from an object such as a hammer are illustrated in U.S. Pat. Nos. 4,875,289; and 4,026,338. Further, the prior art impact designs include projections that are limited in number, that engage the fastener head at less than optimum portions and that are designed to “assist” a primary rotational driver (the blade of a screwdriver) to rotate the fastener.
A problem with the prior art impact extraction designs is that the edges or projections are to few in number or are imbedded sufficiently deep into the fastener head and ultimately “break free” from the fastener head before sufficient rotational force is generated to extract the fastener from the workpiece. Another problem with the prior art designs is that the projections cannot be driven sufficiently deep into the fastener head without damaging the device with a forceful hammer strike. Yet another problem with the prior art designs is that a deformed or damaged fastener head may include portions that cannot be engaged by corresponding projections from the extraction device resulting to few projections engaging the fastener head to provide sufficient rotational force to remove or insert the fastener from or into the workpiece.
A need exits in the art for a fastener impact driver device that includes edges and/or projections sufficient in quantity and design to grasp and rotate a fastener head. Further, the device must be capable of receiving forceful impact without being damaged. Also, the device must be sufficiently adjustable to cause all projections extending therefrom to engage corresponding portions of the fastener head thereby promoting the rotation of the fastener into or from a workpiece.